This dataset contains a list of 1,753 alien vascular plant taxa (i.e., species, infraspecific taxa and hybrids; hereafter species for simplicity) found in Japan and data on the year of first record and pathways of introduction for many, if not all, of these species. The dataset was created during the study documented in the following article: Egawa C. & Koyama A. (2023) Temporal trends in the accumulation of alien vascular plant species through intentional and unintentional introductions in Japan. NeoBiota 83: 179-196. https://doi.org/10.3897/neobiota.83.101416 Procedures for creating the dataset are detailed in the article. Concise explanation of the dataset can be found in the README sheet in the file.